<template>
<div>
    <router-link
     tag="div"
     to="/"
     class="header-abs"
     v-show="showAbs"
    >
      <div class="iconfont header-abs-back" >&#xe605;</div>
    </router-link>

     <div class="header-fixed"
          v-show="!showAbs"
          :style="opacityStyle"
     >
        <router-link to = '/'>
      <div class="iconfont header-fixed-back">&#xe605;</div>
      </router-link>
          景点详情
      </div>
</div>
</template>
<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 50) {
        let opacity = top / 130
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  mounted () {
    window.addEventListener('scroll', this.handleScroll)
  },
  beforeDestroy () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>
<style lang="stylus" scoped>
 @import '~styles/varibles.styl'
     .header-abs
      position: fixed
      left: .2rem
      top: .2rem
      width: .8rem
      height: .8rem
      line-height: .8rem
      border-radius: .4rem
      text-align: center
      background: rgba(0, 0, 0, .8)
      .header-abs-back
       color: #fff
       font-size: .4rem
     .header-fixed
      z-index: 2
      position fixed
      top: 0
      left: 0
      right: 0
      height: .86rem
      font-size:.32rem
      line-height: .86rem
      text-align: center
      color: #fff
      background: $bgColor
     .header-fixed-back
       position: absolute
       top: 0
       left: 0
       width: .64rem
       text-align:center
       font-size: .4rem
       color: #fff
</style>
